Image display devices such as cathode-ray tube (CRT) display devices, liquid crystal displays (LCDs), plasma display panels (PDPs), electroluminescence displays (ELDs), field emission displays (FEDs), touch panels, electronic paper, and tablet PCs are required to be provided with abrasion resistance in order to prevent damage during handling.
In response to such request, a hard coat film having a hard coat (HC) layer on a substrate film, and a hard coat film provided with optical functions such as anti-reflection properties and anti-glare properties have been usually used to improve the abrasion resistance of the image display surfaces of these image display devices.
As an example of hard coat films having a hard coat layer on a substrate film, Patent Literature 1 discloses a hard coat film, wherein a hard coat layer formed using an ultraviolet-curable resin such as pentaerythritol triacrylate (PETA) as a binder component is provided on a substrate film.
However, in the case of a hard coat film provided with a hard coat layer formed using such an ultraviolet-curable resin, it has been difficult to impart sufficient hardness to the hard coat layer (for example, a pencil hardness of 4H or more as measured by a test in accordance with a pencil hardness test specified in JIS K5600-5-4 (1999) at a load of 4.9 N).
Further, hard coat films have been required to have higher performance these days, and there has been a demand for a hard coat film having higher hardness and better abrasion resistance.
Unfortunately, conventional hard coat films cannot fully respond to such a demand.
Patent Literature 2, for example, discloses a hard coat film provided with a hard coat layer containing spherical silica fine particles.
In the case of a hard coat film provided with a hard coat layer containing such spherical silica fine particles, it has been difficult to achieve a hardness of 4H in the pencil hardness test defined above. Further, because materials for forming a hard coat layer are not crosslinkable, a large amount of light must be irradiated during light curing in order to impart high hardness to the hard coat layer, as described in Examples. When a substrate such as a triacetylcellulose film that is susceptible to heat damage is used as a substrate for forming a hard coat layer, it unfortunately results in the formation of visually apparent wrinkles due to heat damage on the substrate caused by polymerization heat during polymerization of the materials for forming the hard coat layer.